2k05gt Posted March 10, 2015 Share #1 Posted March 10, 2015 Using the NDS Retro XM603 Lower Receiver (Semi-Auto) it looks like the original, even the color matches the Original Colt 603 Upper Receiver.I found all original handguards, pencil barrel, buttstock and grip. Included in the picture is a period original Bi-pod and Case, Bayonet and scabbard and Magazines. I even found an M16 chrome Bolt to complete the look.. Link to comment Share on other sites More sharing options...
439th Signal Battalion Posted March 10, 2015 Share #2 Posted March 10, 2015 Very nice build sir. I am amazed at how much both the A1 and SP1 uppers (and complete rifles for that matter) have increased in price over the last couple of years with the parts coming harder and harder to find (at least for me in my area). I used to see/buy super nice, complete uppers from Gunbroker for a fraction of what they are now. Link to comment Share on other sites More sharing options...
Ronny67 Posted March 10, 2015 Share #3 Posted March 10, 2015 I would love to have a AR just like this on some day. Excellent use of original parts! This one turned out VERY well! Thank for sharing! How does she shoot? If you shoot it... Link to comment Share on other sites More sharing options...
2k05gt Posted March 10, 2015 Author Share #4 Posted March 10, 2015 I would love to have a AR just like this on some day. Excellent use of original parts! This one turned out VERY well! Thank for sharing! How does she shoot? If you shoot it... It shoots very well, I was searching for the barrel for a long time, a friend contacted me who is a Military Surplus dealer in Miami and said he picked up a crate full of New/Old 1966 Colt M16 Barrels still wrapped in cosmoline. I had to drill the front sight post and without a jig it was tough. here is what I did; I removed the swivel buckle from the front sight and tapped it, put it on the barrel and went to the range. I put the rifle on the bench and clamped it down, each shot I would adjust the front sight then tighten the bolt on the bottom, I repeated this procedure until the front sight was dead on target. Put it in a drill press and drilled the barrel, pinned it and removed the bolt on the bottom and replace the buckle... Link to comment Share on other sites More sharing options...
MWalsh Posted March 10, 2015 Share #5 Posted March 10, 2015 Very nice! Looks great! Link to comment Share on other sites More sharing options...
blitzkrieg gsd Posted March 14, 2015 Share #6 Posted March 14, 2015 Turned out great looks just like one you would have seen in the jungle in the sixtys. Tell me about these barrels your friend has found and if there are still any for sale. Do you know the twist rate on them the original where 1/12 and 1/14 if I'm not mistaken. We have one of the originals with the fastest twist rate they done the 1/14 I believe. And it shots like a dream but only with the 55gr bullets anything heavier then that tumbles out of the faster twist rate barrels. It's hard to find barrels with that type of fast twist rate anymore. If your friend has some still for sale I would like to talk with him. Link to comment Share on other sites More sharing options...
2k05gt Posted March 16, 2015 Author Share #7 Posted March 16, 2015 Turned out great looks just like one you would have seen in the jungle in the sixtys. Tell me about these barrels your friend has found and if there are still any for sale. Do you know the twist rate on them the original where 1/12 and 1/14 if I'm not mistaken. We have one of the originals with the fastest twist rate they done the 1/14 I believe. And it shots like a dream but only with the 55gr bullets anything heavier then that tumbles out of the faster twist rate barrels. It's hard to find barrels with that type of fast twist rate anymore. If your friend has some still for sale I would like to talk with him.No they sold out in a week. it's hard to find any 20" pencil (Government profile) barrels these days.I believe you meant to say slower twist rate (1:14)The less the twist, the more unstable the round is. (1:14 twist is less than 1:7) 1:14 is 1 revolution in 14 inches, The lower the number of the twist, the faster the twist rate or the faster the bullet will spin. 1:14 was the standard twist rate for the AR-15 (601) 1:12 was from the Late AR-15 (601), XM16 (602), XM16E1 / M16A1 (603) and M16 (604). The M16A2 on there were variants from 1:7, 1:10 and 1:12. Armalite increased the barrel twist to 1:12 to improve accuracy. But when tested in frigid Alaska, accuracy was decreased because of the increased friction from the denser, colder air. Therefore, the barrel twist was eventually increased from 1:12 to 1:10 and eventually to the 1:7 you see it today. Although some bull-barreled AR-15’s and Stoner Sniper Rifles can be found in a 1:9, most of today's issued M-16’s and M-4;s are primarily a 1:7 twist. Anyway, about the barrel, He said they were Colt Experimental made in 1965 (crate was dated), They were not chrome lined but it has a 1:8 twist, I can't find any reference to a 1:8 being used on any Colt or AR rifle, this was a fast twist rate for that time, (1 Revolution in 8 in), so this was setup to shoot the heavier 62gr and up bullet. the only reference I can find is that the Canadian Government wanted a longer range *Sniper" rifle. but they settled on a 1:10 in the M16A2. by then the barrels were chrome lined. so this is a unique barrel, and it shoots my M855 5.56 green tips extremely well. I was expecting to get a 1:12 since that was the standard M16 twist rate, still a bit slow for a 62gr 5.56 bullet but perfect for a 55gr .223 round. shooting a 62gr bullet from a 1:12 or 1:14 would cause the bullet to to have erratic characteristics in flight and decrease accuracy considerably. but also in in reverse, shooting a 45gr bullet or less from a 1:7 twist could cause the jacket to come apart in flight. Link to comment Share on other sites More sharing options...
blitzkrieg gsd Posted March 16, 2015 Share #8 Posted March 16, 2015 I promise that anything more then 55gr won't hit the side of a barn out of the 1-14 twist barrel I have. And your rite I had it backwards I tend to do that from time to time lol. Link to comment Share on other sites More sharing options...
MWalsh Posted March 17, 2015 Share #9 Posted March 17, 2015 I had a friend of mine take a standard A2 and turn it down so that it is the same diameter as an A1 barrel. So, I can do a retro A1 which will shoot like an A2. The upper is already built. You wouldnt know by looking at it that it's not an A1 barrel. Link to comment Share on other sites More sharing options...
215Dave Posted March 17, 2015 Share #10 Posted March 17, 2015 Looks great! I need to get my lower color matched to the upper and my 603 will be complete. Happy shooting! Link to comment Share on other sites More sharing options...
sactroop Posted March 17, 2015 Share #11 Posted March 17, 2015 There's plenty of opportunities out there to get new production A1 profile barrels out there in 1:12, 1:9, 1:7, if you look around. If your looking for a NOS 16A1 barrels that's a different matter. I wouldn't mind adding a 601 and early 603 clone to go with my SP1. Link to comment Share on other sites More sharing options...
215Dave Posted March 18, 2015 Share #12 Posted March 18, 2015 @sactroop Green Mountain Barrels makes a "pencil barrel" profile, in 20" length. I want to say $180..... Link to comment Share on other sites More sharing options...
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